The preparation of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-(4-pyridin-3-yl)pyrimidin -2-ylamino)phenyl]benzamide and the use thereof, especially as an anti-tumour agent, are described in Example 21 of EP-A-0 564 409, which was published on 6 Oct. 1993, and in equivalent applications in numerous other countries. This compound is exemplified in these publications only in free form (not as a salt).
It has now been surprisingly found that a crystal form may under certain conditions be found in the methanesulfonate salt of this compound, which is described hereinafter as β-crystal form, and which has very advantageous properties.